Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
//        InputStream inputStream = new FileInputStream("sum.in");
        OutputStream outputStream = System.out;
//        OutputStream outputStream = new FileOutputStream("sum.out");


//        Path path = Paths.get(URI.create("file:///foo/bar/Main.java"));
//        System.out.print(path.getName(200));

//        Path p = Paths.get("/foo/bar/Main.java");
//        for (Path e : p) {
//            System.out.println(e);
//        }

        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Answer solver = new Answer();
        solver.solve(in, out);
        out.close();
    }
}

class Answer {
    private final int INF = (int) (1e9 + 7);
    private final int MOD = (int) (1e9 + 7);
    private final int MOD1 = (int) (1e6 + 3);
    private final long INF_LONG = (long) (1e18 + 1);


    private List<Integer> getRows(int[][] g, int n, int m) {
        List<Integer> rows = new ArrayList<>();
        for (int i = 0; i < n; i++) {

            int min = Integer.MAX_VALUE;
            for (int j = 0; j < m; j++) {
                if (min > g[i][j]) {
                    min = g[i][j];
                }
            }

            for (int j = 0; j < min; j++) {
                rows.add(i + 1);
            }

            for (int j = 0; j < m; j++) {
                g[i][j] -= min;
            }

        }
        return rows;
    }

    private List<Integer> getCols(int[][] g, int n, int m) {
        List<Integer> cols = new ArrayList<>();
        for (int i = 0; i < m; i++) {

            int min = Integer.MAX_VALUE;
            for (int j = 0; j < n; j++) {
                if (min > g[j][i]) {
                    min = g[j][i];
                }
            }

            for (int j = 0; j < min; j++) {
                cols.add(i + 1);
            }

            for (int j = 0; j < n; j++) {
                g[j][i] -= min;
            }
        }
        return cols;
    }


    private boolean test(int[][] g, int n, int m) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (g[i][j] != 0) {
                    return false;
                }
            }
        }
        return true;
    }

    private void printAns(List<Integer> rows, List<Integer> cols, PrintWriter out) {
        out.println(rows.size() + cols.size());
        for (Integer x : rows) {
            out.println("row " + x);
        }
        for (Integer x : cols) {
            out.println("col " + x);
        }
    }

    public void solve(InputReader in, PrintWriter out) throws IOException {

        int n = in.nextInt();
        int m = in.nextInt();

        int[][] g1 = new int[n][m];
        int[][] g2 = new int[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                g1[i][j] = in.nextInt();
                g2[i][j] = g1[i][j];
            }
        }

        List<Integer> rows1 = getRows(g1, n, m);
        List<Integer> cols1 = getCols(g1, n, m);

        List<Integer> cols2 = getCols(g2, n, m);
        List<Integer> rows2 = getRows(g2, n, m);

        if (!test(g1, n, m) && !test(g2, n, m)) {
            out.print("-1");
            return;
        }

        if (test(g1, n, m)) {
            if (!test(g2, n, m)) {
                printAns(rows1, cols1, out);
            } else {
                if (rows1.size() + cols1.size() < rows2.size() + cols2.size()) {
                    printAns(rows1, cols1, out);
                } else {
                    printAns(rows2, cols2, out);
                }
            }
        } else {
            printAns(rows2, cols2, out);
        }
    }
}

class InputReader {
    private BufferedReader reader;
    private StringTokenizer tokenizer;

    InputReader(InputStream stream) {
        reader = new BufferedReader(new InputStreamReader(stream), 32768);
        tokenizer = null;
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

    public long nextLong() {
        return Long.parseLong(next());
    }
}